fault-injection/cpu: Convert to hotplug state machine

Install the callbacks via the state machine.

This is just a temporary vehicle to keep the interface working for now,
It'll be replaced by the sysfs interface which allows to step through the
hotplug state machine step by step.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160906170457.32393-15-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 41 insertions, 6 deletions

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 7706987c7827..bb6231d13d3a 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -43,6 +43,7 @@ enum cpuhp_state {
         CPUHP_ARM_SHMOBILE_SCU_PREPARE,
         CPUHP_SH_SH3X_PREPARE,
         CPUHP_TIMERS_DEAD,
+        CPUHP_NOTF_ERR_INJ_PREPARE,
         CPUHP_BRINGUP_CPU,
         CPUHP_AP_IDLE_DEAD,
         CPUHP_AP_OFFLINE,
diff --git a/lib/cpu-notifier-error-inject.c b/lib/cpu-notifier-error-inject.c
index 707ca24f7b18..0e2c9a1e958a 100644
--- a/lib/cpu-notifier-error-inject.c
+++ b/lib/cpu-notifier-error-inject.c
@@ -8,16 +8,47 @@ static int priority;
 module_param(priority, int, 0);
 MODULE_PARM_DESC(priority, "specify cpu notifier priority");
 
+#define UP_PREPARE 0
+#define UP_PREPARE_FROZEN 0
+#define DOWN_PREPARE 0
+#define DOWN_PREPARE_FROZEN 0
+
 static struct notifier_err_inject cpu_notifier_err_inject = {
         .actions = {
-                { NOTIFIER_ERR_INJECT_ACTION(CPU_UP_PREPARE) },
-                { NOTIFIER_ERR_INJECT_ACTION(CPU_UP_PREPARE_FROZEN) },
-                { NOTIFIER_ERR_INJECT_ACTION(CPU_DOWN_PREPARE) },
-                { NOTIFIER_ERR_INJECT_ACTION(CPU_DOWN_PREPARE_FROZEN) },
+                { NOTIFIER_ERR_INJECT_ACTION(UP_PREPARE) },
+                { NOTIFIER_ERR_INJECT_ACTION(UP_PREPARE_FROZEN) },
+                { NOTIFIER_ERR_INJECT_ACTION(DOWN_PREPARE) },
+                { NOTIFIER_ERR_INJECT_ACTION(DOWN_PREPARE_FROZEN) },
                 {}
         }
 };
 
+static int notf_err_handle(struct notifier_err_inject_action *action)
+{
+        int ret;
+
+        ret = action->error;
+        if (ret)
+                pr_info("Injecting error (%d) to %s\n", ret, action->name);
+        return ret;
+}
+
+static int notf_err_inj_up_prepare(unsigned int cpu)
+{
+        if (!cpuhp_tasks_frozen)
+                return notf_err_handle(&cpu_notifier_err_inject.actions[0]);
+        else
+                return notf_err_handle(&cpu_notifier_err_inject.actions[1]);
+}
+
+static int notf_err_inj_dead(unsigned int cpu)
+{
+        if (!cpuhp_tasks_frozen)
+                return notf_err_handle(&cpu_notifier_err_inject.actions[2]);
+        else
+                return notf_err_handle(&cpu_notifier_err_inject.actions[3]);
+}
+
 static struct dentry *dir;
 
 static int err_inject_init(void)
@@ -29,7 +60,10 @@ static int err_inject_init(void)
         if (IS_ERR(dir))
                 return PTR_ERR(dir);
 
-        err = register_hotcpu_notifier(&cpu_notifier_err_inject.nb);
+        err = cpuhp_setup_state_nocalls(CPUHP_NOTF_ERR_INJ_PREPARE,
+                                        "cpu-err-notif:prepare",
+                                        notf_err_inj_up_prepare,
+                                        notf_err_inj_dead);
         if (err)
                 debugfs_remove_recursive(dir);
 
@@ -38,7 +72,7 @@ static int err_inject_init(void)
 
 static void err_inject_exit(void)
 {
-        unregister_hotcpu_notifier(&cpu_notifier_err_inject.nb);
+        cpuhp_remove_state_nocalls(CPUHP_NOTF_ERR_INJ_PREPARE);
         debugfs_remove_recursive(dir);
 }